1. Field of the Invention
The invention relates to portable reading lights; and, more particularly, to a light device.
2. Related Art
Reading lights are well known in the art. In my U.S. Pat. No. 5,558,428, I disclose a portable reading light adapted to be worn about the head of a user. The light of the device projects a beam for reading a book or magazine or the like and is adjustable. The light of the device diffuses a beam substantially uniformly over a quadrilateral area so that the user can read a book or magazine with comfort.
Although this light device works quite well, the bulb used, disposed at the head of the user, generates quite a bit of heat. Increasing the intensity of the bulb to increase the amount of light generated would only add to the heat problem.
In my U.S. Pat. No. 5,997,165, I disclose another portable reading light device adapted to be worn about the head of a user or the like. This device utilizes a projection housing adapted to be used as the light source having the terminal end of a fiberoptic mounted therein, the other end extending to a remote lamp unit having a reflector and a light bulb mounted therein.
While this light device also works quite well, fiberoptics are quite expensive and the equipment used to generate the light output is cumbersome and expensive.
In my pending application Ser. No. 09/316,715, filed May 21, 1999, I disclose another type of reading light that generates a bright, focused rectangular light using little power. This reading light uses LEDs as the light source. However, it has been found that, even though this reading light works quite well and projects sufficient light to illuminate a book or the like, most readers, even if they are not aware of it, move their heads (on which the light may be mounted) slightly while reading which causes slight light fall off.
It is an object of this invention to provide a reading light using LEDs as the output of the light source.
It is still further an object of this invention to carry out the foregoing object directing the light source into a beam thereby making efficient use of light.
It is still further an object of this invention to carry out the foregoing objects spreading the light evenly with uniform illumination than prior art devices.
It is another object of this invention to provide a white light having particular value in certain diagnostic procedures.
These and other objects are preferably accomplished by providing a portable reading light device that utilizes LEDs as the light source focused through a single lens. Pulse Width Modulation is used to actuate the LEDs to provide uniform illumination with less heat than a continuously operating LED.